docs: def display_progress(cls, operations):
          """ Display progress of Gandi operations.
  
          polls API every 1 seconds to retrieve status.
          """
          start_crea = datetime.utcnow()
  
          # count number of operations, 3 steps per operation
          if not isinstance(operations, (list, tuple)):
              operations = [operations]
          count_operations = len(operations) * 3
          updating_done = False
          while not updating_done:
              op_score = 0
              for oper in operations:
                  op_ret = cls.call('operation.info', oper['id'])
                  op_step = op_ret['step']
                  if op_step in cls._op_scores:
                      op_score += cls._op_scores[op_step]
                  else:
                      cls.echo('')
                      msg = 'step %s unknown, exiting' % op_step
                      if op_step == 'ERROR':
                          msg = ('An error has occured during operation '
                                 'processing: %s' % op_ret['last_error'])
                      elif op_step == 'SUPPORT':
                          msg = ('An error has occured during operation '
                                 'processing, you must contact Gandi support.')
                      cls.echo(msg)
                      sys.exit(1)
  
              cls.update_progress(float(op_score) / count_operations,
                                  start_crea)
  
              if op_score == count_operations:
                  updating_done = True
  
              time.sleep(cls._poll_freq)
  
          cls.echo('\r')